Researchers of Technische University of Muenchen have succeeded in arranging rod-shaped molecules in a two-dimensional network to form small rotors spontaneously that can rotate as an assembly.
Researchers have built up an extensive nano lattice by allowing cobalt atoms and rod-shaped molecules of sexiphenyl-dicarbonitrile to react with each other on a silver surface. This has resulted in a honeycomb-like lattice automatically assembled with regularity and stability.
When the researchers added further molecular building blocks, the rods spontaneously gathered, typically in groups of three, in a honeycomb cell while neighboring cells remained empty.
Researchers found that three molecules oriented themselves in such a way that the nitrogen ends each faced a phenyl-ring hydrogen atom. This triple-bladed rotor arrangement is so energetically advantageous that the molecules maintain this structure even when thermal energy is applied to rotate it.
The assembly of cell is not round, but hexagonal and hence there are two different possible positions for the rotors formed as a result of the interactions between the outer nitrogen atoms and the hydrogen atoms of the cell wall. Furthermore, the three molecules arrange in a clockwise and a counter-clockwise manner.
For example rods of sexiphenyl-dicarbonitrile can be made to spontaneously form three-bladed rotors and when thermal energy is supplied, they start rotating in their honeycomb-cage.
The discovery of such self-organizing structures hold enormous potential and this discovery can be used to build simple mechanical models to optical or electronic switching,